This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This is the 10th 1-year renewal request of MCA01S027 to the Cheatham lab to support biomolecular simulations of nucleic acids and proteins in their native environment. A key focus is on exposing and fixing deficiencies in the force fields and methods. The primary simulation tool is AMBER and Gaussian, however our group also applies CHARMM, NAMD, AutoDock and Dock.